This invention relates to an information carrier as well as a method and apparatus for manufacturing the same. In the present invention, the term "information carrier" covers a wide range of information carriers that support operating information, input information and the like in a variety of electronic devices, industrial devices and devices for public services. The term "label-carrying surface" for an information carrier covers a wide range of surfaces that indicate the function of information carriers. Examples of such information carriers are keyboards and tablet input units of switchboards, electronic desk-top computers, devices for handling information, and the like. An example of such an information carrier is a push-button switch consisting of a rubber elastomer molded into a dome-shaped configuration and used on a keyboard of a small-size electronic computer or the like. The top surface of the push-button switch forms the key top on which there is generally printed a character switch as a numeral or arithmetic symbol to indicate the function of the key.
In the specifications of Japanese Patent Application Laid-Open No. 57-201688 and U.S. application Ser. No. 380,414 (filed on May 20, 1982, now U.S. Pat. No. 4,500,218 issued Feb. 19, 1985), both commonly-assigned to Toho Kabushiki Kaisha, the same assignee of the subject invention, there is disclosed an information carrier and a method of manufacturing the carrier, in which a pattern is screen printed on a transfer plate through use of a silicone rubber ink and the pattern is embedded in the top of the information carrier, one example of which is a key top. A drawback encountered in this proposed information carrier is that the surface (stationary surface) of the conventional transfer plate bearing the printed pattern is not capable of applying a fixing force to the pattern to fix the pattern against slippage caused by the flow of a molding material within a mold used to form the information carrier. Consequently, when the mold is closed and molding is carried out, the pattern slips on the transfer plate owing to the flow of the material internally of the mold, thereby causing the pattern to sustain a positional shaft, deformation and distortion.
Furthermore, since the transfer plate has a smooth surface, the surface of the molded information carrier is smooth and glossy. This causes the ambient light incident thereon to reflect so that reading the character borne by the carrier is difficult. Moreover, if the surface of the information carrier is too smooth, the finger of the operator clings to the carrier and is somewhat difficult to withdraw from the key top, thereby impeding smooth operation. In addition, dust floating in the air tends to attach itself to a smooth surface and cannot be readily removed from the surface.